Cathode-ray tube



June 29, 1954 E. SANFORD CATHODE-RAY TUBE Filed May 29. 1952 F l' g.

mb N F0 @n Fm 50E onf EEB N 0 N XL EMEA AEE ETL/ u Nif L G E E B 00 INVENTOR. EM/L SANFORD ATTORNEYS Patented June 29, 1954 cATnoDE-RA'Y TUBE Emil Sanford, Clifton, N. J., assignor to Allen B.

Du Mont Laboratorie corporation of Delawa s, Inc., Clifton, N. J., a re Application May 29, 1952, Serial No. 290,642

The present invention relates to cathode-ray tubes and particularly to color-image reproducing cathode-ray tubes.

In cathode-ray tubes utilizing a plurality of electron guns and phosphors of different light generating characteristics to reproduce images in color, a perforated mask is generally interposed between the electron guns and the phosphor areas in such a manner that each of the respective phosphor areas of different light generating characteristics are exposed to the cathode-ray beam of only one of the plurality of guns. Obtaining suitable alignment. of the mask heretofore has been a slow, expensive manual operation not suitable to the mass assembly of such tubes.

Accordingly, it is an object of the present invention to provide an improved cathode-ray tube of the color-image reproducing type utilizing a perforated mask, the alignment of which may be obtained with considerably more Speed and econ- 01115.

Another object of the present invention is toy provide a cathode-ray tube of the color-image reproducing type wherein the alignment of the mask may be made by means external to the tube.

These and other objects of the present invention may be obtained in accordance with the present invention by providing a cathode-ray tube having the perforated mask suspended in the tube by meansv passing through the tube envelope and adjustable externally of the tube. For a better understanding of the invention reference may be had to the drawing in which Figure 1 is a view of a cathode-ray tube embodying the present invention with parts of the tube illustrated in cross-section and parts broken away; Figure 2 is a view of the cathode-ray tube of Figure l taken alongzthe line 2-2 and Figure 3 is an enlarged fragmentary view of the fluorescent screen and mask of the tube.

Referring now to the drawing and particularly to Figure l there is illustrated a cathode-ray tube comprising an envelope which consists of a glass neck portion 2 flaring outwardly at one end where it is joined to a metal cone portion 4 having a glass face plate 5 enclosing its enlarged end. The metal cone portion 4 is provided with radially and axially extending flange portions 8 and Ill respectively within which there is supported the fluorescent screen I2 and a perforated mask I4.

The fluorescent screen I2 comprises a support plate I 6 which is usually of glass or some similar suitable transparent material on which there is formed on the side of the support exposed to the electron beams of the tube, a plurality of phosphor areas I8 of red, blue and green fluorescent characteristics arranged to form triads as illutrated in Figure 3. The fluorescent screen I2 is 8 Claims. (Cl. 313-70) supported in an annular ring 20 which is supported against the inner wall of the axially extending flange portion l0. Spring clips 22 hold the fluorescent screen in the annular ring.

The perforated mask I4 comprises a perforated circular metal plate supported in an annular ring 24. The ring and perforated plate are suspended in the space of the cone dened by the radially and axially extending flanges and I by means of a plurality of elongated pins 26. The pins aresecured to the annular ring 24 and extend through the radially extending flanged portion, as shown. Where the pins 2t pass through the flange they are secured thereto in some Y suitable manner, as by welding, and have a portion thereof exposed externally of the tube envelope. The perforated mask I4 is provided with apertures which are equally spaced with a single aperture for each of the dot triads comprising the primary red, blue and green color phosphors.

Mounted in the neck portion 2 of the tube there are a plurality of electron guns 28 lfor directing beams of electrons against the fluorescent screen. As shown, there is an electron gun for each of the different color phosphors. The electron guns 28 are aligned in the tube so that the electron beams of the guns are focused.y on the perforated plate I4. As will be seen from Figure 3, with this arrangement of the guns, each gun will be aligned to project an electron beam through the apertures of the perforated mask to bombard one of the color phospors dots of the triads.

To obtain suitable alignment of the perforated mask in the tube, the exposed ends of the pins 25 may be' moved about the point of juncture, or welded jointof the pin with the metal cone. This movement being slight in order to obtain alignment will not overstress the joint so as to cause leakage. The adjustment of the mask through movement of the pins may be obtained by a manual manipulation of the ends of the pins or by a jig fixture adapted to be fitted around the metal cone of the tube.

It will be seen that with a device such as I have described herein, there is eliminated the careful and tedious adjustments prior to assembly of the tube.

What I claim is:

1. A cathode-ray tube comprising an envelope, a fluorescent screen positioned in said envelope,

kan electron gun positioned in said envelope, a

perforated mask positioned in said envelope between said electron gunv and said screen, and means xedly attached to said mask internally of said envelope and extending from said mask through said envelopeI and externally thereof whereby the position of said mask may be adjusted to a fixed position by manipulation of that portion of said means externally of said tube.

2. A cathode-ray tube comprising an envelope having a neck portion, a fluorescent screen positioned in said envelope, an electron gun positioned in said neck portion, a perforated mask positioned in said envelope between said electron gun and said screen and means nxedly attached to said mask internally of said envelope and extending from said mask through said envelope' and externally thereof whereby the position of said mask may be adjusted. to ai fixed. position-by manipulation of that portion ofs'aid means externally of said tube.

3. A cathode-ray tube comprising an envelope having a neck portion, a iiuorescent screen positioned in said envelope, an electron gun posi-' tioned in said neck portion, a perforated mask positioned in said envelope.' between saidI electron gun and said screen and means iixedly attached to said mask internally of said envelope and extending from said mask through said envelope and externally thereof whereby the' position of said mask may be adjusted to a fixedr position by manipulation of that portionof said means externally of said tube.

4. A cathode-ray tubeV comprising an envelope having a neck portion, a iiuorescent screen positioned in said envelope, a plurality of electron guns positioned in said neck portion, a perforated mask positioned in said envelope between said electron guns and said screen and an elongated member iixedly attached to said mask internally of said envelope and extending from saidmask through said envelope and externally thereof whereby the position of said mask may be adjusted to a fixed position by manipulation of that portion of said elongated member externally of said tube.

5. A cathode-ray tube comprising an envelope lia-ving aneck portion, a fluorescent screen positioned inl saidV envelope said screen including a plurality of different' color phosphor areas, a plurality of electron guns disposed' in said neck portion, one electron gun for each of said different color phosphor areas, a perforated mask positionedv in said' envelope between said screen and saidY guns, and a plurality of elongated members fix'edly attachedV to said mask internally of said envelope and extending therefrom through said envelope and externally thereof said ineinbers being secured to said' envelope by means stressable to permitV adjustment of said mask to a fixed". position by movement of said elongated members externally of said envelope.

S. A cathode-ray tube comprising an envelope having a' glass neck portion and a metal portion sealed thereto, a fluorescent screen positioned in said metal portion, a plurality of electron gunsV positioned in` said neck portion,v a perforated` mask positioned in said metal portion betweensaid screen' and said electron guns and a plurality 6 of elongated metallic members iixedly attached in spaced relation to saidmask internally of said envelope and extending through said metal portion and externally thereof, said members being joined to said metal portion by a welded junction to prevent leakage at the juncture said junction being stressable to permit manipulation of said members externally of said tube to adjust the position of said mask to a iixed position therein.

7'. AL cathodelray tube comprising an envelope having a glassneek portion and a metal conical portionl sealed thereto, a uorescent screen positioned in said conical portion said screen comprising a plurality .of contiguous phosphor areas of different fluorescent color characteristics arranged symmetrically in triads on said screen, a plurality of electron guns" disposed said neck portion, oneg'u'n forv eachl of said color phosphors, a perforated mask positioned saidenvelope between said screen and said gunsaid mask having perforar-tions, one for each of said triads, and a plurality of elongated metallic members flxedly attached in spaced relation to said mask internally of said envelope and extending through said conical Aportion and externally thereof, said members beingjoined to said conioa1 portion by a welded junction to form a sealed joint stressable to permit manipulation of said members externally of said tube to adjust the position of said mask to a iixed' position therein.

8. A cathode-ray tube comprising an envelope having a glass neck portion and a rneta'l conical portion sealed' thereto, said' metal conical portion' having a radially extendingV flange, a fluorescent screenpositioned in said conical portion adjacent said' ange, saids'creen comprising a plurality of contiguous phosphor areas of diiferent fluorescent color characteristics, an electron gun' disposed in said neck portion, an apertured' mask positioned in said envelope adjacent said :Harige andV between said screen and said gun, and a plurality of elongated rods having one end flxedly attached to said mask at substantially equi-distant positions and1 extending substantially perpendicularly therefrom andsubstantially perpendicula-rly through said flange and externally thereof, said rods being secured at a position intermediate the ends thereof to said iiange by a welded junction to form a sealed joint, said welded junction being stressable by manipulations of the end external of said rods to adjust the position` of said mask in said envelope.

References Cited in the file of this patent UNTED' STATES' PATENTS Number v ame Y Date 2,611,099 Jenny sept. 16,1952 'REIGN PATENTS 0 nimmer country Date 5893345 Great Brita-ia v June is', i947 

